Machine for grinding internal surfaces concentric with external surfaces



Aprll 21, 1953 M. H. ARMS ET 2,635,395

MACHINE FOR GRINDING INTER L SURFACES CONCENTRIC WITH EXTERNAL SURFACES Filed May 19, 1951 5 Sheets-Sheet l Aprll 21, 1953 M. H. ARMS ET AL 2,635,395

MACHINE GRINDING INTER L SUR ES CONCEN c WITH EXTERNA URFA Filed May 19, 1951 5 Sheets-Sheet 2 2,635,395 SURFACES CES April 21, 1953 M. H. ARMS ET AL MACHINE FOR GRINDING INTERNAL CONCENTRIC WITH EXTERNAL SURF'A 5 Sheets-Sheet 3 Filed May 19, 1951 Jzzwzzf'im fir ail/ m April 21, 1953 M. H. ARMS ET AL 2,635,395

MACHINE FOR GRINDING INTERNAL SURFACES CONCENTRIC WITH EXTERNAL SURFACES 5 Sheets-Sheet 4 Filed May 19, 1951 DRIVING P4147"! Bar/9776A! 2 s m AS w m Aprnfi 21, 1953 M. H. ARMS ET AL MACHINE FOR GRINDING INTERN CONCENTRIC WITH EXTERNAL 5 Sheets-Sheet 5 Filed May 19, 1951 172w win JZ/ff/XZJ fad 05; 69%;]

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Patented Apr. 21, 1953 MACHINE FOR GRINDING INTERNAL SUR- FACES SURFACES CONCENTEIC WITH EXTERNAL Merton H. Arms and Paul A. Grobey, Springfield, Vt., assignors to Bryant Chucking Grinder Company, Springfield, Vt., a corporation of Vermont Application May 19, 1951, Serial No. 227,172

13 Claims.

It is sometimes desired to finish internal sur faces concentric with external surfaces which have previously been finished, and it is an object of this invention to provide a method and mechanism by which this may be accomplished.

In accordance with this invention, therefore, the work piece having the finished external surface is pressed against the end face of a rotating member while supported from its finished external face somewhat eccentric to the axis of rotation and with the interior unobstructed so that a tool, such as a grinding wheel, may be presented to the internal face and machine it accurately concentric with its finished outer face, as the piece is being rotated with the rotating member.

For a complete understanding of this invention, reference may be had to the accompanying drawings in which Figure l is a front elevation of an internal grinding machine embodying the invention.

Figure 2 is a sectional view to a larger scale on line 2--Z of Figure 1.

. Figures 3 and 4 are sectional views on lines 3-3 and 44, respectively, of Figure 2.

Figure 5 is a fragmentary view similar to a portion of Figure 2, but with parts in different relative positions and between grinding cycles.

Figure 6 is a fragmentary view similar to a portion of Figure 4, but showing a modified construction.

Figure '7 is a diagrammatic view illustrating the forces tending to rotate the work piece when the work spindle and the grinding wheel are rotating in the same direction.

Figure 8 is a closed force system diagram corresponding to Figure 7 Figure 9 is a view similar to Figure 7, but showing the work piece and grinding wheel being rotated in opposite directions.

Figure 10 is a closed force system diagram corresponding to Figure 9.

Figure 11 is a view similar to a portion of Figure l, but showing a modified construction.

Figure 12 is a top plan view partly broken away of the structure shown in Figure 11.

Figure 13 is a front end elevation of the same.

Referring to Figure 1 of the drawings, the machine comprises a bed I carrying a head 2 in which is journaled a tubular rotary work- 2 shaft 4 axially to the right as viewed in Figure 1 as far as permitted by a suitable stop 8. The spindle may be provided with suitable means by which it may be rotated, a grooved belt pulley 9 being shown for this purpose in Figure 1.

As best shown in Figure 4, the forward end of the spindle 3 has secured thereto an annular guide member Ill and this guide member may be provided on its rear face with an internally tapered annular face H shaped to correspond with the standard spindle nose the mating end of the spindle 3 being provided with standard spindle nose configuration. Screws I2 may secure the guide member if! in position. This guide member has a central bore l3 concentric with the spindle and within which is axially slidable an annular work-engaging member !5 provided at its forward end with an annular face 16 outwardly of a tapered face l'l, this annular face it serving to engage and impart rotation to one or more work pieces. Two work pieces 20 have been illustrated, arranged in contact with each other, the inner of these only bearing against the annular face 16, but one or more than two might .be so positioned if desired.

The shaft 4 may be hollow and provided with a tubular extension 2! which may be secured as by threading into the rear end of the workengaging member l5. Through this shaft 4 and its pipe extension 2| and the work-engaging member i5, coolant may be caused to flow into contact with the inner annular faces of the work pieces 20 while they are being machined. The rear end of the shaft 4 may be provided with any suitable nipple 22 for the attachment or" a flexible pipe through which the coolant may be conducted to the work pieces.

It will be noted that the spring 6 tends to press the member forwardly into contact with the work piece adjacent thereto, and this pressure tends to hold the outer work piece, where more than one is to be machined at one time, against a second annular work-engaging member 25. As shown best in Figure 4, this annular workengaging member 25 is carried by a ring member '26 to which it is secured as by screws 2'1, a flange 28 of the annular member 25 and a second flange 29 of the member 26 serving to clamp between them the inner raceway 30 of a ball bearing. The outer raceway 3[ of this bearing is engaged between a pair of annular members 32 and 33, the member 33 having a marginal flange which may be secured to a stationary annular frame 34 which is secured to the head 2 as by screws 35. The work-engaging member 25 is thus mounted for free rotation coaxially with the spindle 3. It is spaced a fixed distance from the forward end of th guiding member [0, and it is provided with a central annular extension 40 which provides an abutment for contact with the adjacent work piecev ihe work piece or work pieces are thus clamped between the annular faces 15 and 40 by the spring 6 and with their inner faces open to access by an internal finishing tool such as the grinding wheel 42. This wheel 42 is shown as carried by a spindle 43 mounted in a grinding wheel head 44 suitably supported for motion into and out of grinding relation to the internal faces of the work piece on a carriage 46 carried by the machine bed I.

Suitable means may be provided for relatively moving the wheel and work heads in order to bring the tool, such as the grinding wheel 42, into and out of operative relation to the work pieces and to feed them relatively, but as such means is old and well known in the art, no detailed showing is believed necessary.

It will be noted from an inspection of Figure 4 that the internal diameter of the work pieces, which are shown as internal ball bearing raceways, is very small compared to the internal diameter of the ball bearing upon which the annular work-engaging member 2 is supported, and since, in the constructions of Figures 1 to 4, inclusive, there is no positive drive between the work spindle and this member, it may be found desirable to impart a rotational impulse to this member in the same direction as the rotation of the work spindle in order to prevent undesired slippage between it and the work pieces, or between the work piece faces or between the inner work pieces and the driving member [5. Where this is desired, a portion of the rotating elements, which include the work-engaging member 25, and as herein shown the annular member 29, may be provided with outwardly extending vanes 50 upon which may impinge a jet of air as from a nozzle 5| (see Figure 1), this nozzle being so positioned as to direct the air against the vanes in a direction to tend to rotate the member 29 and with it the member 25 in the desired direction.

If desired, however, the outer work-engaging member may be positively driven, such a construction being illustrated in Figures 11 to 13, inclusive, in which the work spindle is provided with a second belt pulley I over which a belt i I i is engaged, this belt also engaging about a pulley H2 on a jack shaft H3 which may be journaled in suitable spaced bearings on the work head 2. A pulley H4 on the jack shaft H3 is connected through a belt H'5 with a pulley member H6 integral with or carried by the outer work-engaging member 25a, these parts being so proportioned that the work-engaging member 25a is driven at substantially the same angular velocity and in the same direction as the Work-holding spindle 3.

Means are provided for retaining the work pieces with their externally finished faces 53 in somewhat eccentric relation to the spindle 3 during the internal finishing operation. To this end, a support 50 or a pair of such supports, which may be provided if desired, with concaved inner faces 6| for engagement with the external faces 53 of the work pieces, are suitably supported with these faces 6| positioned for supporting the work pieces. As shown each support 60 may be provided with screw and slot connections as at 62 the screws 63 of which are threaded into holes in the stationary support 34. Adjusting screws 65 threaded into radial openings 56 in each support 60 may have their heads 6! engaging the internal face of an arcuate portion 68 of the member 34. To this arcuate portion 58 and shorter arcuate portions 69, the member 33 is secured as previously described. These spaced supports 50 provide positioning for the work pieces during the machining operation, and it may be desired to retain the work pieces in such position positively. Such retaining means may comprise rollers 10 carried by an arm ll pivoted on a shaft 12 secured to the member 34. This arm 'H may have a crank extension '13 having a pivot opening 14 to which any suitable actuating means 15 may be attached in order to rock the arm i2 between its lowered position with the rollers 10 engaging the work pieces and holding them against the supports 68, as shown in Figure 2, and in lifted position shown in Figure 5, in which the rollers 10 are out of contact with the work pieces and permit them to descend freely as through a suitable chute T5. The arm H may also be provided with one or more ejecting fingers 18, which when the arm H is turned to the position of Figure 5, will engage the work pieces and push them out of supporting relation with respect to the members and cause them to pass into the upper end of a discharge chute I9 by which they are conducted away from machining position. When the rollers K1 are being lowered, they engage the work piece or pieces which have been allowed to descend through the chute 1G and force them between the workclamping faces is and 40, the engagement of the inner work piece on the inclined face I T acting to Wedge the member l5 rearwardly against the pressure of the spring 6 until the work piece or pieces are in position for the inside bore-finishing operation. Similarly the rocking of the arm H in the opposite direction, which forces the work piece or pieces out of finishing position, permits the spring 6 to move the work-engaging member 15 outwardly to a limited extent in position to have the inner end of the next succeeding work piece engage the tapered portion H and wedge the members I5 rearwardly when this work piece is moved downwardly into machining position.

Means are preferably provided for feeding the work pieces to machining position in succession while holding back those higher up within the chute 16. For this purpose a separator 80 may be employed, pivoted at BI and being provided with a pair of inwardly facing separator fingers 82 and 83 so positioned that when the separator is in the angular position in Figure 5, the finger 83 holds back all the work pieces above it, while the finger 82 is removed from obstructing position and allows the work pieces previously between the fingers 82 and 83 to descend through the chute 16 toward working position. When the separator 80 is rocked in the opposite direction to a position shown in Figure 2, the finger 83 is removed from obstructing position, allowing the work pieces to descend into contact with the finger $2 which is then in work-obstructing position, and prevents the descent of any of the work pieces through the chute 16. This separator may be moved in suitable timed relation to the other parts of the machine in any desired manner and as well known in the art.

In Figure 3 a mounting for the arm H is shown with a single ejecting finger 18 shown as secured to this arm. This ejecting finger I8 is secured as by a double screw and slot connection at to a block 92 having a T slot connection with thearm l l. The crank extension 13 may be provided with an actuating rod 15.

In Figure 6 a modified construction is shown in which in place of the work supports Eli with their stationary inner concaved faces, a support 60a is used which carries a rotatable roller 99 with which the work piece or pieces contact. In this figure, also, there is shown a work gage having circular gaging portions I and i0! for rough and finish work sizing, mounted within the work-engaging member [a and movable axially at desired times to test the progress of the internal grinding operation in the well known manner. In Figures 7 to there is illustrated diagrammatically the effects of the rotation of the work clamping members and of the grinding wheel where the work is arranged somewhat eccentric to the axis of the spindle in producing rotation of the Work piece and in holding the work piece with its finished external face against the supports 60. In Figure 7 there is illustrated the condition where the work-clamping means is rotated in the same direction as the grinding Wheel. The grinding wheel 62 is presented to the internal diameter of the work piece 29 and with the clockwise direction of rotation of this wheel, its rotation in removing stock from the work will react against the work with two forces, a radial force through the center of the wheel and the point of contact with the work in the direction O-X and a frictional force in the direction Z--X tangentially to the wheel, producing a resultant A.

The work-clamping elements are shown eccentric to the work piece by the amount W-Y. The rotation of the clamping plates will tend to revolve the work and also tend to produce a translation of the center of the work in a circle of the radius WY, this radius being denoted by c. This motion is resisted by the shoes 60 which causes a resultant pressure which will be perpendicular to the line through the rotational center of the clamping means and the work, this being indicated by the arrow B. If the center of the work is to remain stationary, these forces 'A and B must be opposed by the forces developed on the supports 65) of such magnitude and directionas to give a closed system of forces and the forces on the shoe supports 60 will each comprise a frictional component at ,f and a radial component g which results in forces in the directions C and D. Referring to Figure 8, these forces have been arranged in a closed system in the direction shown in Figure 7, forces in the direction'C and D opposing'the forces in the directions A and B.

Similarly in Figure 9 where the work is shown rotating counterclockwise and the wheel rotating clockwise, the forces A, B, C and D may be determined, which must be arranged in a closed system such as is shown in Figure 10 for balance to be eifected.

It will be noted from the foregoing that it will be necessary that the pressures exerted by the rotation of the clamping means and the rotation of the grinding wheel be such as to exert pressure in a direction between the supports 60 so that the work piece will be pressed against these supports. It will, of course, be quite impossible 'to maintain all work pieces in exact coaxial relation to the work spindle in view of the fact that their outside diameters cannot be exactly the same, and the supports with which they engage, even if initially properly set, wear, so that the work pieces could not be maintained coaxial with the spindle. Thus the coincidence of the axis of the work and the axis of the spindle would only occur under certain conditions, but it is not necessary that they should occur and there are indeed some advantages in having them not coaxial, so long as the offset is in proper relation to the supports so that the work is pressed thereagainst. Under such conditions there will, of course, be a slight sliding motion between the work pieces and their clamping means, and the centers of two Or three work pieces clamped together will not coincide unless by accident. However, the work pieces will be ground concentric with their outside diameters even though their axes may not coincide. In order thatthe roller 70 may engage work pieces of slightly different diameters, the rollers may be mounted for slight differential or equalizing motion, and to this end their pivot shaft 10a is shown in Figure '4 as mounted in yieldable rubber or the like bushings 10b in the arm H which permits tilting of the shaft with corresponding variations in position of the peripheries of the rollers.

From the foregoing description of certain embodiments of this invention it should be evident to those skilled in the art that various further changes and modifications may be made without departing from the spirit or scope of the invention.

We claim:

1. In combination, a rotary work spindle, a work-engaging member carried by said spindle and having a work-engaging face, means with which an externally finished face of a work piece may be engaged supporting said work piece in engagement with said member work engaging face, a member mounted for rotation with said spindle and having a portion operatively engageable with a portion of the work piece opposite to the engagement of said work piece with said member work engaging face, means for clamping the work piece between said member work engaging face and said member portion, means for rotating said spindle, and a tool having a work-engaging portion movable away from the rotational axis of said spindle into engagement with an internal face of said work piece and effective to exert pressure on said work piece against said finished face engaging means and to tool said internal face in concentric relation to said exteral face as said spindle rotates.

2. In combination, a rotary work spindle, a work-engaging member carried for rotation with said spindle and movable axially thereof, a second work-engaging member mounted for free rotation coaxially with said spindle and spaced from said spindle-carrying member, means engageable with an external annular finished face of a work piece for holding said work piece between said members, means for rotating said spindle, means yieldingly pressing said work-engaging members toward each other to clamp the work piece therebetween, and means acting on said second work-engaging member tending to rotate said second work-engaging member in the same direction as the rotation of said spindle.

3. In combination, a rotary work spindle, a work-engaging member carried for rotation with said spindle and movable axially thereof, a second work-engaging member mounted for free rotation coaxially with said spindle and spaced from said spindle-carrying member, means engageable with an external annular finished face of a work piece for holding said work piece between said members, means for rotating said spindle, means yieldingly pressing said work-engaging members toward each other to clamp the work piece therebetween, vanes projecting from said second work-engaging member, and an air jet positioned to deliver air against said vanes in direction tending to rotate said second member in the same direction as the rotation of said spindle.

4. In combination, a rotary work spindle, a work-engaging member carried for rotation with said spindle and movable axially thereof, a second work-engaging member mounted for free rotation coaxiall with said spindle and spaced from said spindle-carried member, an element with which an external annular face of the work piece may engage when the work piece is between said work-engaging members, a movable member, means for moving said movable member from and to a position to hold the work piece against said element, means for rotating said spindle, and means yieldingly pressing said work-engaging members toward each other to clamp the work piece therebetween.

5. In combination, a rotary work spindle, a work-engaging member carried for rotation with said spindle and movable axially thereof, a second work-engaging member mounted for free rotation coaxially with said spindle and spaced from said spindle-carried member, an element with which an external annular face of the work piece may engage when the work piece is in between said work-engaging members, a movable member having a pair of positions, and means for moving said movable member between said two positions in one of which one of said portions engages and holds the work piece in contact with said element, and the motion of which movable member to the other of said positions causes the other of said portions to eject the work piece from between said work-engaging members, means for rotating said spindle, and means yieldingly pressing said work-engaging members toward each other to clamp the work piece therebetween.

6. In combination, a rotary work spindle, a work-engaging member carried for rotation with said spindle, a second work-engaging member mounted for free rotation coaxially with said spindle and spaced from said spindle-carried member, an element with which an external annular face of the work piece may engage when the work piece is between said work-engaging members, a movable member having a pair of positions, and means for moving said movable member between said two positions in one of which one of said portions engages and holds the work piece in contact with said element, and the motion of which movable member to the other of said positions causes the other of said portions to eject the work piece from between said workengaging members, means for rotating said spindle, one of said work-engaging members being axially movable and having a tapered face with which a work piece moving toward said between position may engage and force said movable work-engaging member from the other of said work-engaging members suiiiciently for said work piece to pass between said work-engaging members into said driven relation thereto, and means for yieldingly pressing said movable work-engaging member toward the other workengaging member.

'7. In combination, a rotary work spindle, a work-engaging member carried for rotation with said spindle and movable axially themof, a leoond work-engaging member mounted for free rotation coaxially with said spindle and spaced from said spindle-carrying member, means engageable with an external annular finished lace of a work piece for holding said work piece between said members, means for rotating said spindle, means yieldingly pressing said work-engaging members toward each other to clamp the work piece therebetween, and means acting on said second work-engaging member tending to rotate said second work-engaging member in the same direction as the rotation of said spindle. said work-engaging members clamping the work piece eccentric to said spindle axis and so disposed that the rotation of said members exerts a force component pressing the work piece against said holding means.

8. In combination, a rotary work spindle, a work-engaging member carried by said spindle and having a work-engaging face, means with which an externally finished face of a work piece may be engaged supporting said work piece in engagement with said member work-engaging face, a member mounted for rotation with said spindle and having a portion operatively engageable with a portion of the work piece opposite to the engagement of said work piece with said member work-engaging face, means for clamping the work piece between said member work-engaging face and said member portion, means for rotating said spindle, a rotary grinding wheel having its grinding surface portion movable away from the rotational axis of said spindle into engagement with an internal face of said work piece. and means for rotating said grinding wheel, said rotary work-engaging members clamping the work piece eccentric to said spindle axis and so disposed that the rotation of said work-engaging means and said grinding wheel when said grinding surface portion engages the work piece exert force components pressing the work piece with its externally finished face against said means with which said face engages.

9. In combination, a rotary work spindle, a work-engaging member carried for rotation with said spindle and movable axially thereof, a second work-engaging member mounted for free r0- tation coaxially with said spindle and spaced from said spindle-carried member, means engageable with an external annular finished face of a work piece supporting said work piece between said members, means actuable to hold said work piece in engagement with said engaging members. means for rotating said spindle, means yielding- 1y pressing said work-engaging members toward each other to clamp the work piece therebetween. and means for rotating said second work-engaging member at substantially the same angular velocity and in the same direction as said work spindle.

10. In combination, a rotary work spindle, a work-engaging member carried for rotation with said spindle and movable axially thereof. a second work-engaging member mounted for free rotation coaxially with said spindle and spaced from said spindle-carried member, an element with which an external annular face of the work piece may engage when the work piece is between d o a g members, a movable member, means for moving said movable member from and to a position to hold the work piece against said element, means for rotating said spindle, means yieldingly pressing said work-engaging members toward each other to clamp the work piece therebetween, and means for rotatin said second work-engaging member at substantially the same angular velocity and in the same direction as said work spindle.

11. In combination, a rotary work spindle, a work-engaging member carried for rotation with said spindle and movable axially thereof, a second work-engaging member mounted for free r0- tation coaxially with said spindle and spaced from said spindle-carried member, means engageable with an external annular finished face of a work piece supporting said work piece between said members, means actuable to hold said work piece in engagement with said engaging members, means for rotating said spindle, means yieldingly pressing said work-engaging members toward each other to clamp the Work piece therebetween, a jack shaft parallel to said spindle, means for rotating said jack shaft from said spindle, and means for rotating said second workengaging member from said jack shaft at substantially the same angular velocity and in the same direction as said work spindle.

12. In combination, a pair of axially spaced substantially coaxial rotary work-engaging members between which a tubular work piece having an externally finished annular face may be 10 clamped, at least one of which members is annular, a support with which said face may be engaged, and a tool mounted for movement through said annular member and engageable with the internal face of said work piece.

13. In combination, a pair of axially spaced substantially coaxial work-engaging members between which a pair of work pieces having externally finished annular faces may be clamped, a support between said members with which said faces may be engaged, a pair of rollers one for each of said work pieces, a shaft on which said rollers are journaled, a member yieldingly supporting said shaft, and means for actuating said member to press said rollers against said work pieces and said work pieces against said support.

MERTON H. ARMS. PAUL A. GROBEY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,078,416 Sauer Apr. 27, 1937 2,440,148 Madison Apr, 20, 1948 2,478,562 Binns et a1 Aug. 9, 1949 2,478,607 Theler et al. Aug. 9, 1949 

